physics AS unit 2 section 8.1 - speed and velocity

Investing:
in this section we ask:
  • what's the difference between displacement and distance?
  • what is the difference between instantaneous speed and average speed?
  • when does it matter whether you use speed or velocity?

Extending:
for those looking for a more rigorous introduction to this, take a look at this lecture from Prof. Walter Lewin of MIT: